U.S. Pat. No. 7,317,534 B2 provides a measuring method comprising a measuring unit with a film layer having a detecting area where a target molecule is fixed to the surface thereof and a reference area where no ligand is fixed to the surface thereof. A photo detector detects the intensities of light beams reflected in total internal reflection at the detecting area and reference area, respectively. Further, the result of measurement in the detecting area is calibrated on the bases of the result of measurement in the reference area.
US2005/0052655 A1 describes an interferometer comprising an optical body adapted in operation to mount a measurement area comprising a film which is capable of acting as a two dimensional environment for surface plasmons and an adjacent reference area, an optical beam generation means for irradiating the reference and measurement areas with radiation capable of generating surface plasmon resonance, optical means for combining radiation reflected from the reference and measurement areas, and pixelated detection means for generating data representing two dimensional images of the combined radiation beams.